1 files changed, 451 insertions, 0 deletions
diff --git a/drivers/watchdog/alim1535_wdt.c b/drivers/watchdog/alim1535_wdt.c
new file mode 100644
index 000000000..bfb9a91ca
--- /dev/null
+++ b/drivers/watchdog/alim1535_wdt.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pci.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#define WATCHDOG_NAME "ALi_M1535"
+#define WATCHDOG_TIMEOUT 60	/* 60 sec default timeout */
+
+/* internal variables */
+static unsigned long ali_is_open;
+static char ali_expect_release;
+static struct pci_dev *ali_pci;
+static u32 ali_timeout_bits;		/* stores the computed timeout */
+static DEFINE_SPINLOCK(ali_lock);	/* Guards the hardware */
+
+/* module parameters */
+static int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+		"Watchdog timeout in seconds. (0 < timeout < 18000, default="
+				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+		"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/*
+ *	ali_start	-	start watchdog countdown
+ *
+ *	Starts the timer running providing the timer has a counter
+ *	configuration set.
+ */
+
+static void ali_start(void)
+{
+	u32 val;
+
+	spin_lock(&ali_lock);
+
+	pci_read_config_dword(ali_pci, 0xCC, &val);
+	val &= ~0x3F;	/* Mask count */
+	val |= (1 << 25) | ali_timeout_bits;
+	pci_write_config_dword(ali_pci, 0xCC, val);
+
+	spin_unlock(&ali_lock);
+}
+
+/*
+ *	ali_stop	-	stop the timer countdown
+ *
+ *	Stop the ALi watchdog countdown
+ */
+
+static void ali_stop(void)
+{
+	u32 val;
+
+	spin_lock(&ali_lock);
+
+	pci_read_config_dword(ali_pci, 0xCC, &val);
+	val &= ~0x3F;		/* Mask count to zero (disabled) */
+	val &= ~(1 << 25);	/* and for safety mask the reset enable */
+	pci_write_config_dword(ali_pci, 0xCC, val);
+
+	spin_unlock(&ali_lock);
+}
+
+/*
+ *	ali_keepalive	-	send a keepalive to the watchdog
+ *
+ *	Send a keepalive to the timer (actually we restart the timer).
+ */
+
+static void ali_keepalive(void)
+{
+	ali_start();
+}
+
+/*
+ *	ali_settimer	-	compute the timer reload value
+ *	@t: time in seconds
+ *
+ *	Computes the timeout values needed
+ */
+
+static int ali_settimer(int t)
+{
+	if (t < 0)
+		return -EINVAL;
+	else if (t < 60)
+		ali_timeout_bits = t|(1 << 6);
+	else if (t < 3600)
+		ali_timeout_bits = (t / 60)|(1 << 7);
+	else if (t < 18000)
+		ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
+	else
+		return -EINVAL;
+
+	timeout = t;
+	return 0;
+}
+
+/*
+ *	/dev/watchdog handling
+ */
+
+/*
+ *	ali_write	-	writes to ALi watchdog
+ *	@file: file from VFS
+ *	@data: user address of data
+ *	@len: length of data
+ *	@ppos: pointer to the file offset
+ *
+ *	Handle a write to the ALi watchdog. Writing to the file pings
+ *	the watchdog and resets it. Writing the magic 'V' sequence allows
+ *	the next close to turn off the watchdog.
+ */
+
+static ssize_t ali_write(struct file *file, const char __user *data,
+						size_t len, loff_t *ppos)
+{
+	/* See if we got the magic character 'V' and reload the timer */
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/* note: just in case someone wrote the
+			   magic character five months ago... */
+			ali_expect_release = 0;
+
+			/* scan to see whether or not we got
+			   the magic character */
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					ali_expect_release = 42;
+			}
+		}
+
+		/* someone wrote to us, we should reload the timer */
+		ali_start();
+	}
+	return len;
+}
+
+/*
+ *	ali_ioctl	-	handle watchdog ioctls
+ *	@file: VFS file pointer
+ *	@cmd: ioctl number
+ *	@arg: arguments to the ioctl
+ *
+ *	Handle the watchdog ioctls supported by the ALi driver. Really
+ *	we want an extension to enable irq ack monitoring and the like
+ */
+
+static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static const struct watchdog_info ident = {
+		.options =		WDIOF_KEEPALIVEPING |
+					WDIOF_SETTIMEOUT |
+					WDIOF_MAGICCLOSE,
+		.firmware_version =	0,
+		.identity =		"ALi M1535 WatchDog Timer",
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+	case WDIOC_SETOPTIONS:
+	{
+		int new_options, retval = -EINVAL;
+
+		if (get_user(new_options, p))
+			return -EFAULT;
+		if (new_options & WDIOS_DISABLECARD) {
+			ali_stop();
+			retval = 0;
+		}
+		if (new_options & WDIOS_ENABLECARD) {
+			ali_start();
+			retval = 0;
+		}
+		return retval;
+	}
+	case WDIOC_KEEPALIVE:
+		ali_keepalive();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+	{
+		int new_timeout;
+		if (get_user(new_timeout, p))
+			return -EFAULT;
+		if (ali_settimer(new_timeout))
+			return -EINVAL;
+		ali_keepalive();
+	}
+		fallthrough;
+	case WDIOC_GETTIMEOUT:
+		return put_user(timeout, p);
+	default:
+		return -ENOTTY;
+	}
+}
+
+/*
+ *	ali_open	-	handle open of ali watchdog
+ *	@inode: inode from VFS
+ *	@file: file from VFS
+ *
+ *	Open the ALi watchdog device. Ensure only one person opens it
+ *	at a time. Also start the watchdog running.
+ */
+
+static int ali_open(struct inode *inode, struct file *file)
+{
+	/* /dev/watchdog can only be opened once */
+	if (test_and_set_bit(0, &ali_is_open))
+		return -EBUSY;
+
+	/* Activate */
+	ali_start();
+	return stream_open(inode, file);
+}
+
+/*
+ *	ali_release	-	close an ALi watchdog
+ *	@inode: inode from VFS
+ *	@file: file from VFS
+ *
+ *	Close the ALi watchdog device. Actual shutdown of the timer
+ *	only occurs if the magic sequence has been set.
+ */
+
+static int ali_release(struct inode *inode, struct file *file)
+{
+	/*
+	 *      Shut off the timer.
+	 */
+	if (ali_expect_release == 42)
+		ali_stop();
+	else {
+		pr_crit("Unexpected close, not stopping watchdog!\n");
+		ali_keepalive();
+	}
+	clear_bit(0, &ali_is_open);
+	ali_expect_release = 0;
+	return 0;
+}
+
+/*
+ *	ali_notify_sys	-	System down notifier
+ *
+ *	Notifier for system down
+ */
+
+
+static int ali_notify_sys(struct notifier_block *this,
+					unsigned long code, void *unused)
+{
+	if (code == SYS_DOWN || code == SYS_HALT)
+		ali_stop();		/* Turn the WDT off */
+	return NOTIFY_DONE;
+}
+
+/*
+ *	Data for PCI driver interface
+ *
+ *	This data only exists for exporting the supported
+ *	PCI ids via MODULE_DEVICE_TABLE.  We do not actually
+ *	register a pci_driver, because someone else might one day
+ *	want to register another driver on the same PCI id.
+ */
+
+static const struct pci_device_id ali_pci_tbl[] __used = {
+	{ PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
+	{ PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
+	{ 0, },
+};
+MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
+
+/*
+ *	ali_find_watchdog	-	find a 1535 and 7101
+ *
+ *	Scans the PCI hardware for a 1535 series bridge and matching 7101
+ *	watchdog device. This may be overtight but it is better to be safe
+ */
+
+static int __init ali_find_watchdog(void)
+{
+	struct pci_dev *pdev;
+	u32 wdog;
+
+	/* Check for a 1533/1535 series bridge */
+	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
+	if (pdev == NULL)
+		pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
+	if (pdev == NULL)
+		return -ENODEV;
+	pci_dev_put(pdev);
+
+	/* Check for the a 7101 PMU */
+	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
+	if (pdev == NULL)
+		return -ENODEV;
+
+	if (pci_enable_device(pdev)) {
+		pci_dev_put(pdev);
+		return -EIO;
+	}
+
+	ali_pci = pdev;
+
+	/*
+	 *	Initialize the timer bits
+	 */
+	pci_read_config_dword(pdev, 0xCC, &wdog);
+
+	/* Timer bits */
+	wdog &= ~0x3F;
+	/* Issued events */
+	wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
+	/* No monitor bits */
+	wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));
+
+	pci_write_config_dword(pdev, 0xCC, wdog);
+
+	return 0;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static const struct file_operations ali_fops = {
+	.owner		=	THIS_MODULE,
+	.llseek		=	no_llseek,
+	.write		=	ali_write,
+	.unlocked_ioctl =	ali_ioctl,
+	.compat_ioctl	= 	compat_ptr_ioctl,
+	.open		=	ali_open,
+	.release	=	ali_release,
+};
+
+static struct miscdevice ali_miscdev = {
+	.minor =	WATCHDOG_MINOR,
+	.name =		"watchdog",
+	.fops =		&ali_fops,
+};
+
+static struct notifier_block ali_notifier = {
+	.notifier_call =	ali_notify_sys,
+};
+
+/*
+ *	watchdog_init	-	module initialiser
+ *
+ *	Scan for a suitable watchdog and if so initialize it. Return an error
+ *	if we cannot, the error causes the module to unload
+ */
+
+static int __init watchdog_init(void)
+{
+	int ret;
+
+	/* Check whether or not the hardware watchdog is there */
+	if (ali_find_watchdog() != 0)
+		return -ENODEV;
+
+	/* Check that the timeout value is within it's range;
+	   if not reset to the default */
+	if (timeout < 1 || timeout >= 18000) {
+		timeout = WATCHDOG_TIMEOUT;
+		pr_info("timeout value must be 0 < timeout < 18000, using %d\n",
+			timeout);
+	}
+
+	/* Calculate the watchdog's timeout */
+	ali_settimer(timeout);
+
+	ret = register_reboot_notifier(&ali_notifier);
+	if (ret != 0) {
+		pr_err("cannot register reboot notifier (err=%d)\n", ret);
+		goto out;
+	}
+
+	ret = misc_register(&ali_miscdev);
+	if (ret != 0) {
+		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+		       WATCHDOG_MINOR, ret);
+		goto unreg_reboot;
+	}
+
+	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
+		timeout, nowayout);
+
+out:
+	return ret;
+unreg_reboot:
+	unregister_reboot_notifier(&ali_notifier);
+	goto out;
+}
+
+/*
+ *	watchdog_exit	-	module de-initialiser
+ *
+ *	Called while unloading a successfully installed watchdog module.
+ */
+
+static void __exit watchdog_exit(void)
+{
+	/* Stop the timer before we leave */
+	ali_stop();
+
+	/* Deregister */
+	misc_deregister(&ali_miscdev);
+	unregister_reboot_notifier(&ali_notifier);
+	pci_dev_put(ali_pci);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
+MODULE_LICENSE("GPL");